The International Congress of Radiation Research has convened every four years since 1958. It has taken place twice previously in North America, 1958 in Burlington, Vermont, 1974 in Seattle, Washington, and in other countries in the intervening years. The Radiation Research Society, headquartered in Reston, Virginia, has been selected by the International Association for Radiation Research to host the next Congress, the ninth, to be held July 7-12, 1991. Since the Radiation Research Society (founded in 1952) is a North American Organization and because of favorable organizational and site conditions, the decision has been made to hold the Ninth Congress in Toronto. The Congress id multidisciplinary in nature covering all aspects of radiation science from physics, chemistry, biology to medicine. It provides the only opportunity for participants from many countries to meet and share recent research findings. The number of registrants at the Congress has been made estimated as 1325. The program is currently being developed and will include Congress lectures, symposia, workshops and poster sessions for proffered papers. A major effort is being made to ensure that the symposia and workshops are truly interdisciplinary, since it is felt that radiation science has developed to a state where this is the mode in which most rapid progress can be made. Financial support for this Congress is being requested. The total budget for the meeting is $700,000 (this includes invited speaker support, young investigator travel (about 100), publication of programs, proceedings etc., administration, audiovisual, and plenary events). At the present time funds have been received from the IARR (25,000), from the 8th Congress ($8,000) and the Radiation Research Society has earmarked $200,000 for support of the Congress. From the projected attendance it is expected that $350,000 in registration will be received. Thus the shortfall between current projections of expenditure and income is $117,000. It is hoped to meet this short fall with grants from government agencies of $117,000. The present request is for $27,000 from NIH. These latter funds, and all funds received from U.S. agencies, will be used to support partially the attendance of 50 United States Young Investigators, (funded at $700 each) and to assist in the essential Publication costs (Proceedings, Programs etc.) associated with the Congress.